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<h1 class="title">QSGOpacityNode 类</h1>
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<p>The <a href="qsgopacitynode.html">QSGOpacityNode</a> class is used to change opacity of nodes. <a href="#details">更多...</a></p>
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<tr><td class="memItemLeft rightAlign topAlign">头文件：</td><td class="memItemRight bottomAlign">   <span class="preprocessor">#include &lt;QSGOpacityNode&gt;</span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += quick</td></tr><tr><td class="memItemLeft rightAlign topAlign">继承自：</td><td class="memItemRight bottomAlign"> <a href="qsgnode.html">QSGNode</a></td></tr></table></div><ul>
<li><a href="qsgopacitynode-members.html">所有成员的列表，包括继承成员</a></li>
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<h2 id="public-functions">公用函数</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qsgopacitynode.html#QSGOpacityNode">QSGOpacityNode</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qsgopacitynode.html#dtor.QSGOpacityNode">~QSGOpacityNode</a></b>() override</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> qreal </td><td class="memItemRight bottomAlign"><b><a href="qsgopacitynode.html#opacity">opacity</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qsgopacitynode.html#setOpacity">setOpacity</a></b>(qreal <i>opacity</i>)</td></tr>
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<li class="fn">20 个公用函数继承自<a href="qsgnode.html#public-functions">QSGNode</a></li>
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<h2 id="details">详细信息</h2>
<p>The <a href="qsgopacitynode.html">QSGOpacityNode</a> class is used to change opacity of nodes.</p>
<p>Opacity applies to its subtree and can be nested. Multiple opacity nodes will be accumulated by multiplying their opacity. The accumulation happens as part of the rendering.</p>
<p>When nested opacity gets below a certain threshold, the subtree might be marked as blocked, causing <a href="qsgnode.html#isSubtreeBlocked">isSubtreeBlocked</a>() to return true. This is done for performance reasons.</p>
<p><b>Note: </b>All classes with QSG prefix should be used solely on the scene graph's rendering thread. See <a href="qtquick-visualcanvas-scenegraph.html#scene-graph-and-rendering">Scene Graph and Rendering</a> for more information.</p></div>
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<h2>成员函数文档</h2>
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<h3 class="fn" id="QSGOpacityNode"><a name="QSGOpacityNode"></a>QSGOpacityNode::<span class="name">QSGOpacityNode</span>()</h3>
<p>Constructs an opacity node with a default opacity of 1.</p>
<p>Opacity accumulates downwards in the scene graph so a node with two <a href="qsgopacitynode.html">QSGOpacityNode</a> instances above it, both with opacity of 0.5, will have effective opacity of 0.25.</p>
<p>The default opacity of nodes is 1.</p>
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<h3 class="fn" id="dtor.QSGOpacityNode"><a name="dtor.QSGOpacityNode"></a><code>[override virtual] </code>QSGOpacityNode::<span class="name">~QSGOpacityNode</span>()</h3>
<p>Deletes the opacity node.</p>
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<h3 class="fn" id="opacity"><a name="opacity"></a><span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> QSGOpacityNode::<span class="name">opacity</span>() const</h3>
<p>Returns this opacity node's opacity.</p>
<p><b>请参考 </b><a href="qsgopacitynode.html#setOpacity">setOpacity</a>()。</p>
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<h3 class="fn" id="setOpacity"><a name="setOpacity"></a><span class="type">void</span> QSGOpacityNode::<span class="name">setOpacity</span>(<span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> <i>opacity</i>)</h3>
<p>Sets the opacity of this node to <i>opacity</i>.</p>
<p>Before rendering the graph, the renderer will do an update pass over the subtree to propagate the opacity to its children.</p>
<p>The value will be bounded to the range 0 to 1.</p>
<p><b>请参考 </b><a href="qsgopacitynode.html#opacity">opacity</a>()。</p>
<!-- @@@setOpacity -->
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